Housing assembly for oil cooled electrical apparatus

ABSTRACT

The invention relates to electrical apparatus of substantial size which includes an outer container and a unit insertable in the container which can be readily withdrawn for the purposes of repair or inspection. The insertable unit consists of an oilcooled lower part and an upper control part. The container has an internal shoulder which is engaged by the upper control part of the unit when the unit is inserted in the container. Struts pivotally connected to the lower end of the unit serve to guide the unit during its withdrawal from the container and to serve as support legs for the unit after it is withdrawn. When the unit is in its withdrawn position the struts rest on the internal shoulder of the container. The struts fold under the unit when it is inserted into the container.

Lehmann HOUSING ASSEMBLY FOR OIL COOLED ELECTRICAL APPARATUS 1451 Dec.31, 1974 FOREIGN PATENTS OR APPLICATIONS 1,808,887 10/1970 Germany317/101 R Primary Examiner-Laramie E. Askin [57] ABSTRACT The inventionrelates to electrical apparatus of substantial size which includes anouter container and a unit insertable in the'container which can bereadily withdrawn. for, the purposes of repair or inspection. Theinsertable unit consists of an oil-cooled lower part and an uppercontrol part. The container has an internal shoulder which is engaged bythe upper control part of the unit when the unit is inserted in thecontainer. Struts pivotally connected to the lower end of the unit serveto guide the unit during its withdrawal from the container and to serveas support legs for the unit after it is withdrawn. When the unit is inits withdrawn position the struts rest on the internal shoulder of thecontainer. The struts fold under the unit when it is inserted into thecontainer.

3 Claims, 5 Drawing Figures CONTROL UNIT [75] Inventor: Kjeld Lehmann,Sonderborg,

Denmark [73] Assignee: Danfoss A/S, Nordhorg, Denmark [22] Filed: Nov.12, 1973 [21] Appl. No.: 415,116

[30] Foreign Application Priority Data Nov. 14, 1972 Germany 2255688 521u.s.c1....- 174/52 R, 174/17 L F, 312/29, 312/312,317/101R [51] Int. Cl.H05k 5/00 [58] Field of Search 174/17 R, 17 LP, 52 R; 200/50 AA, 150 JA;317/99, 101 R, 101 CB, 120; 336/58, 90, 92, 94; 339/34; 220/17;312/21-30, 247, 312

[56] References Cited 3 UNITED STATES PATENTS 3,066,207 11/1962 Duenke..L ZOO/1501A I POWER UNIT PATENTED W33 1 I974 SHEET 1 [1F 2 CONTROL UNIT CON TROL UNIT POWER UNIT PATENTED [1533 1 4 SHEET 2 [IF 2 ELECTRICALCOMPONENTS) HOUSING ASSEMBLY FOR OIL COOLED ELECTRICAL APPARATUS I Theinvention relates 'to an electrical apparatus, and in particular to acontrol apparatus with an oil-cooled power part and a control partdisposed thereabove, in which an insertable unit carrying electricalcomponents is adapted to be withdrawn from a casing which can be supportfor the purpose of repair, inspection or the like.

This is generally not possible at the place where the apparatus isinstalled since suitable surfaces for depositing the insertable unit arenot available and in the case of oil-cooleditems of apparatus,contamination would be caused by the dripping oil.

The object of the invention is to provide an electrical apparatus of theinitially described kind which can be having a shoulder on its innersurface, and by the insertable unit carrying at its lower end stayswhich can be displaced in both directions between a position withinthese side-walls and a splayed position in which their span exceeds thedistance between the side-walls.

In this construction the casing itself is used for supporting thewithdrawn unit. The stays hold the insertable unit at such alevel thatall the electrical components are, readily accessible. In the case ofoil-cooled items of apparatus the oil is able to drip back directly intothe casing. b

It is particularly advantageous if each stay can be pivoted about anaxis parallel to the shoulders, can be swung flat against-the bottom ofthe insertable unit in the normal position, and from there can bepivoted downwards and outwards through an angle of somewhat more than90. Such swingable stays occupy 'no additional space in the normalposition, but have a certain length which enables the insertable unit tobe supported, when withdrawn, ata certain distance above the shoulders.This, means that in the inspection position the insertable unit islocated at a distance above the casing or that the shoulders can'beprovided at a position downwardly removed from the top of the easing bya selectable distance.

In particular the distance separating the shoulders from the top of thecasing may be approximately equal to the length of the stays.

This is of particular importance when the shoulders form the lower limitof a wider part of the casing that, in the normal position, accommodatesa portion of the insertable unit that has a greater cross-section thanthe portion disposed therebelow and that rests on the shoulders. Thisresults in a space-saving construction in which the shoulders arespecifically designed to receive the weight of the insertable unit.

The stays are advantageously subjected toa spring force which displacesthem outwardly. If the insertable 'unit is lifted, the staysautomatically move into the splayed position in which they can supportthemselves on the shoulders.

Further, guides intended to engage the stays can be provided in thecasing, these guides displacing the stays when the insertable unit islowered into the normal position. I

With spring-loaded swingable stays it suffices to use, as the guides,inclined rails which extend from a point close to the shoulders to apoint close to the middle of the base.

In order to enable the stays to be independent of the guides when theseare supported on the shoulders, it is preferred that the stays shouldassume a predetermined outer splayed position in which the lower ends ofthe stays rest approximately at the points where the shoulders mergewith upper portions of the walls, and that these portions of the wallsshould slightly overlap the insertable unit in its raised position, forthe purpose of forming a lateral abutment. When the insertable unit isdisplaced laterally against one of the abutments, the stay on theopposite side is completely released from its shoulder and can be heldin this'position by slightly inclining the insertable unit. By lateraldisplacement of the insertable unit to bring it against the secondabutment, it is also possible to remove the second stay from itsshoulder.

In accordance with a further featureof the invention, at least oneside-wall of the casing may have, above the shoulder, an opening ofwhich the size exceeds the cross-section of a multiple contact plugintended for use with the apparatus, and this opening may be closed by acover plate which carries water-tight cable-inlet bushes. This openingenables operations to be carried out on the stays independently of theautomatic return movement. It offers the further advantage that afterremoval of the cover plate, the multiple contact plug can be completelywithdrawn from the casing so that it does not interfere'with the liftingof the insertable unit.

Particular advantage accrues ifthe insertable unit has handles at itsupper part. Generally, no crane or equivalent means is available at theplace where the apparatus is installed. Since the insertable unit hasonly to be raised through a certain distance, these handles suffice forthe purpose even if the apparatus is relatively heavy.

In one form of construction, the insertable unit has at its upper, partplug-in printed-circuit boards which are secured and guided by means ofa swingable cover, and the handles are formed as an extension of theframe of the swingable cover, which frame is held in its closed positionby a robust locking means suited to the weight of the insertable unit.

Each shoulder preferably forms the upper ends of cooling ribs whichproject outwardly from each sidewall. This feature enables a relativelysmall thickness of wall to be used and despite this to providesufficient stability for supporting the weight of the inserted unit.

The invention will now be described in greater detail by reference to anembodiment illustrated diagrammatically in the annexed drawing, inwhich:

FIG. 1 shows a diagrammatic cross-section through the apparatus of theinvention in its normal position and with the cover removed,

FIG. 2 shows the apparatus of the invention in the raised position forinspection, and, in dotted lines, an intermediate position,

FIG. 3 is a side view of the upper part ofthe insertable unit seen inthe direction of the arrow A of FIG. 2,

FIG. 4 shows on a greater scale a section through the left-hand upperpart of the casing seen in FIG. 1, and

FIG. is a side view of a stay in the guide. The casing 1 consists of twoshorter side-walls 2, two

- longer side-walls 3 and a base 4. An insertable unit 5 vided withcooling ribs 9, the positions of which arev merely indicated roughly inFIG. 1 but which are illustrated more precisely in FIG. 4. Above eachshoulder the side-wall is continued by a wall portion 10.

Provided at the bottom of the insertable unit 5 are stays 11 which canpivot about spindles 12 and which in the normal position occupy theflattened-out position illustrated in FIG. 1. The free ends 13 engagebehind guide rails 14 which take the form of simple angle irons securedto the side-walls 2 and 3 and'extending from a point near shoulder 8 toa point near the middle of the base. FIG. 5 shows a stay 11 made of wirebent to the required shape, this stay being guided by its free ends 13.

The stays 11 are acted upon by the force of a spring, not illustrated,which swings them downwards and outwards. Thus, when the insertable unit5 is raised, the free ends 13 slide outwardly along the guides 14(dotted position shown in FIG. 2) and are automatically brought into theposition in which the free ends 13 bear on the shoulders 8. The widestsplayed position of the stays 11 is such that they occupy approximatelythe position illustrated in FIG. 2 in which the free ends are lo-' catedat points where the shoulders 8 merge with the wall portions lO. In thisposition the entire insertable unit is readily accessible, and it can beinspected and repaired. Oil dripping from the work-performing part 6passes directly back into the casing l.

The height of the wall portions is such that, in the inspectionposition, they overlap the insertable unit 5 to a certain extent, sothat abutments 15 are provided against lateral displacement of thisinsertable unit. In the abutting position the free end 13 of theopposite stay 11 occupies a position exactly above the guide 14. Bymeans of a slight tilting movement this free end 13 can be inserted intothe guide. If the insertable unit 5 is then moved against the oppositeabutment 15, the free end 13 of the other stay 11 can also be broughtinto its associated guide 14. When the insertable unit 5 is lowered, thestays 11 are then automatically returned into the flattened out positionillustrated in FIG. 1.

Provided on the control part 7 are two handles 16 with the aid of whichthe insertable unit 5 can be conveniently raised. These handles areextensions of a swingable-cover 17 that extends into the central plane,and that can be brought into the position 17', shown in dash-and-dotlines, for the purpose of inserting plug-in printed-circuit boards 18.In the withdrawn position however, the swingable cover holds thesepush-in boards firmly between its lower face and the other frame 19. Itmust be secured in this position by means of a strong stud or otherlocking device 20. The positions of other components 21 of the controlpart 7 are merely indicated in an approximate manner.

As shown in FIG. 4, an opening 22 is provided in the wall portion10'above the shoulder 8, the size of this opening being such that amultiple contact plug 23 can be passed through it. The opening 22 isclosed by a cover plate 24 in which are provided bushes 25 through whichcables 26 can be passed in a water-tight manner. The cover plate 24 issecured to the side-wall 2 by means of screws 27 which extend intoprojections 28.

Before the insertable unit 5 is removed from the easing 1, the coverplate 24 can be unscrewed and removed together with the multiple contactplug. The space above the shoulders can therefore be completely occupiedby the control part 7. When the insertable unit is in the inspectionposition, the presence of the opening 22 enables the stay resting on theshoulder 8 also to be pushed back into the guide 14 by hand.

I claim:

1. Electrical apparatus comprising an upwardly open casing having aninternal shoulder, an assembly located within said casing and movablefrom a position fully inserted in said casing to a position withdrawnfrom said casing, comprising an oil cooled lower unit and an uppercontrol unit, said upper unit engaging said casing shoulder when saidassembly is in its fully inserted position in said casing, internalguide means in said casing, strut means having ends connected to thelower end of said lower unit and having portions thereof engageable withsaid guide means, said portions of said strut means being engageablewith said internal shoulder of said casing when said assembly is in saidposition withdrawn from said casing.

2. Electrical apparatus according to claim 1 wherein said strut meansare pivotally connected to said lower attached to the internal walls ofsaid casing.

1. Electrical apparatus comprising an upwardly open casing having aninternal shoulder, an assembly located within said casing and movablefrom a position fully inserted in said casing to a position withdrawnfrom said casing, comprising an oil cooled lower unit and an uppercontrol unit, said upper unit engaging said casing shoulder when saidassembly is in its fully inserted position in said casing, internalguide means in said casing, strut means having ends connected to thelower end of said lower unit and having portions thereof engageable withsaid guide means, said portions of said strut means being engageablewith said internal shoulder of said casing when said assembly is in saidposition withdrawn from said casing.
 2. Electrical apparatus accordingto claim 1 wherein said strut means are pivotally connected to saidlower unit and collapse to a horizontal position when said assembly isin its fully inserted position.
 3. Electrical apparatus according toclaim 2 wherein said guide means are generally vertically extendingrails attached to the internal walls of said casing.